a) Field of the Invention
This invention relates to an adjusting and fixing device for seats, like automobile seats, in particular for the adjustment of the back rest vis-a-vis the seat part, where a fixed mounting is arranged. This mounting is joined with an adjustable mounting (which transfers the adjusting movement) for the back rest by a gearing defining the position of these fittings with each other. This gearing can be driven by means of a cam section. Here the gearing is formed by a radial toothed wheel belonging to a mounting and an internal geared wheel of the other mounting catching into the other one and the counter gearings are arranged at the mountings. Here the cam section is formed by two wedge segments regionally encompassing the bearing of the adjustable mounting. These two wedge segments are inclined against each other. The wedge segments are encompassed by the bearing of the fixed mounting and the narrow sides of the wedge segments can be admitted by the arm of a driver designed as bearing bush, whereas an energy accumulator pressing these away from each other for a radial play reduction catches between the wide sides of the wedge segments.
b) Description of the Related Art
An adjusting and fixing device for seats of the type described at the outset is known from the DE 44 36 101 A1. Here a bush type driver with an arm formed single piece as it catches between the narrow sides of the wedge segments forming a cam section. The wedge segments are pressed away from each other by an energy accumulator at their broad sides. Thus an adjustment of the cam section can be achieved at the tolerance running through during the adjustment movement in the bearing as well as in the toothing and with that a radial play reduction is made possible. In the case of this previously known solution the single piece design of the driver simplifies indeed the production and also the assembly of the hinge brace, however, the problem of the run-off of the back rest is not solved by the power impacts applied on it during the dynamic operation of the automobile. The gearing consisting of the toothed wheels and the cam section formed by the wedge segments is indeed self locking in the case of acutely occurring load due to frictional stop, the run-off of the back rest, however, cannot be prevented absolutely in the case of repeated power impacts occurring for a longer duration of time. In the solution according to the DE 38 19 346 A1 it was already proposed to add a wrap spring brake to the hinge brace for the assured clamping of the back rest in the locked state. This wrap spring brake, however, represents an additional construction element, which requires space on the one hand and leads to a considerable rise in price of the hinge brace on the other.